Field of the Invention
The present invention relates to a zoom lens, and a lens barrel and an image pickup apparatus using the same.
Description of the Related Art
A zoom lens to be used in an image pickup apparatus is desired to be a zoom lens which is small-sized and in which, various aberrations are corrected favorably. As a zoom lens which meets such requirements, a zoom lens of a negative-lead type has been known. In the negative-lead type zoom lens, a lens unit having a negative refractive power is disposed nearest to an object.
As a zoom lens which is negative-lead type and which includes three lens units, a zoom lenses disclosed in Japanese Patent Application Laid-open Publication No. Hei 2-238418, and Japanese Patent No. 4840909 are available. The zoom lenses in the Japanese Patent Application Laid-open Publication No. Hei 2-238418 and Japanese Patent No. 4840909 include in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a negative refractive power.